Heidi Montag and Spencer Pratt recently shared that they are expecting their first child, and Cavallari -- who was wearing a Rebecca Vallance Harris skirt -- told ET's Nischelle Turner that she's been chatting with the mom-to-be "all the time" about motherhood. "Heidi has been asking me lots of baby questions," she shared while at the launch of her jewelry line, Uncommon James, at Fig & Olive in Hollywood, California, on Thursday. "I'm so excited for her. I know she's been wanting a baby for a while."

The mother of three revealed that the first question Montag asked her was about baby names. "I was like, 'Heidi, this is your baby. ...It's what you want to name your baby,'" she quipped. "I sent her a whole list of things I loved as a as a mom [during] the first six months, because I remember being a first-time mom, I [didn't] really have anyone I could turn to."

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The 30-year-old reality star said that she also gave advice to her other Hills co-star, Audrina Patridge, when she welcomed a baby girl last June with husband Corey Bohan. "Audrina reached out a lot when she was pregnant. It's really cool that they feel comfortable enough to come to me and that they look to me for that kind of advice."

As for the advice she has for new moms, Cavallari dished, "It can be overwhelming. It's the cliché things like sleep when the baby is sleeping, and just, like, knowing everything is a phase -- knowing that everything will pass."

"The first six months are hard. They are really hard," she admitted. "Just know it will be over, you will be sleeping again. It gets easier. I thought it got easier as it went on, so everything is a phase."

Cavallari is also about to make a big change in her life as she and her husband, 33-year-old NFL pro Jay Cutler, are moving from Chicago, Illinois, to Nashville, Tennessee. "We have actually had our house [in Nashville] for about six years. We would spend summers there in the off-season," she noted. "This has always been the plan. The plan was always to move to Nashville when Jay was done with football, but even if [he] were to play, I would still move to Nashville with the kids and stay put."

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She further explained, "Whatever he ends up doing, it would be for such a short amount of time. I don't want to bounce my kids around too much. I would just rather move to Nashville, get them situated [and] get them in their school."